1. Field of the Disclosure
The present invention relates to semiconductor devices, and, more particularly, to a method for fabricating a semiconductor device that can improve conductivity of a channel region in the semiconductor device.
2. Discussion of the Related Art
The conductivity of the channel region in an MOS transistor is controlled by a gate electrode. That is, a current driving capability of a conductive channel is controlled by the gate electrode isolated from the channel region by a thin insulating layer (e.g., a gate oxide) formed on the channel region.
The channel is formed by an application of an appropriate control voltage to the gate electrode. The conductivity of the channel region varies with a dopant concentration and the mobility of the charge carriers in the channel region. The conductivity of the channel region is a major factor in determining the performance of a MOS transistor (e.g., a PMOS transistor).
As semiconductor devices become smaller, mobility of hole charge carriers in a PMOS transistor is reduced, and a desired drain current may become difficult to achieve.